on 02.06.2017 at 10:50:27 you’ve tried to save a data in the folder ‘L***’ on your device ‘Android’ ID: ‘androidc348723896’.
This operation was not successful, as you lack write access to this folder.
Your data has been dropped and replaced with the original data on your device to ensure data integrity.

with the Gmail app, there is no problem

With P9-Lite and Android6 and the standard mail there is no problem

We also use A Sony Expiria Z5 with Android7 and the standard mail app with this mobile phone there are no problems

Any ideas What I can adjust the P9-Lite with Android7 and the default mail app so this Z-Push error does not occur

The log does show no sync request nor the sending of the email, but it gave away that the folder “Lohr” is a shared folder (probably via the static configuration, right?).

Then the short answer is: please double check if the user no write permissions on this folder. If he doesn’t the folder is treated as “read-only” and any action the user performs there will be suppressed and the user will get these emails.

@Sebastian
would be helpful, to have a switch, to silently ignore any changes in this folder. The folder is a RO address book, no one can change the content, Unfortunately Android 7 seems to modify data in this folder and we see no possibility to stop Android 7 to do so.

Please add an folder based switch to silently discard changes in this folder.